Railway signaling



A n'l 9, 1929. P ATZ k 1308 524 RAILWAY S I GNALI NG Filed Dec. 2, 1925 INVENTOR' PAUL u'nz TORNEY Patented A r. 9,1929.

UNiTED T A T j.

PAUL 'I'ETZ, OF BERLIN, GERMANY, ASSIGNOR 'IO GESELLSCHAFT FUR DRA'HTLOSE TELEGRAPHIE M. B. H. HALLESCHES, OF BERLIN, GERMANY, A. CORPORATION 01E GERMANY.

RAILWAY SIGNAL'ING.

Application filed December 2, 1925,'S.e1ia1 No. 72,650, and in Germany December 13, 1924-.

This invention relates to the art of railway. signaling and is designed to produce an automatic railway signal which is both simple and dependable inits operation.

'Heretofore it has been suggested to mount oscillation generators such as tube trans-- mitters upon moving trains for the purposes of signaling thereto. In these systems as the train passes over a track signal the state of oscillation of the generator is changed and a suitableindicator operated by means of a relay. These devices have been found unsatisfactory for the reason that its certainty of operation depends upon the instability of the oscillatory state of the tube transmitter; that is, the signal is transmitted by an alteration in the state of oscillation of the afore-mentioned generator, and the necessary change in the state of oscillation is comparatively high in order to transmit the signal with certainty.

In the present invention I provide an arrangementwhich is free from the drawbacks outlined above; my system is based upon the null-method. T mount a balanced bridge upon the engine or any one of the cars of the train, which bridge consists of two arms having alternating current resistances therein. With the diagonal branch of the said bridge I unite the indicating device. As the train passes over the track signaling device, one of the branches becomes coupled thereto, which results in a change in the impedance of one of the arms of the balanced, bridge, whereby the balance is destroyed and there is a flow of current between the zero points. This current is in turn picked up by a suitable amplifying means which in turn operates a relay to in dicate the signal transmitted.

The manner in which I carry out my invention will be better understood from the following description when read in connecthe structure of the car.

coupled to the track device by, means of the transformer K. It may be found desirable to couple the circuit S to a track device also. The zero branch of the bridge is coupled to an audion E in the anode circuit of which I provide a relay R, which relay is employed to actuate the indicating device. The present arrangement is merely an example of one embodiment of my invention it being understood that the same may be modified in various Ways. In any case, however, I find'it desirable to use tuned circuits, it not being necessary for S, and S to be in current resonance, for they may also be arranged to be in voltage resonance. Alsothe amplifying device maybe eliminated and the indicator actuated directly by the current flowing between thezero points of the bridge.

In order that the coupling between the bridge branch and the track device may be as close as possible, I may use iron-cored coils the latter being so disposed that the coupling coil of the track device as Well as the coupling coil leading to the bridge arm are spaced aparta distance limited only by The cores furthermore should be so formed that the magnetic circuit is closed through the locomotive wheels, the rails, and a special armature for the coil of a track device. There is thus provided a complete magnetic path.

.Having thus described my invention what I. claim is:

1. In a device of the class described,a train mechanism comprising a closed, balanced bridge one arm of said bridge comprising a tuned circuit including an inductance, a stationary track impedance of fixed value, adapted to cooperate with the inductance of said tuned circuit to change the tuning of said circuit and unbalance said bridge, a zero branch connected across a pair of neutral points of said bridge, and an amplifier having an input circuit coupled to said zero branch, said input circuit being l nene gized when said bridge is balanced.

2. 1 a railway signal device an alternati'ng current generator, a balanced bridge connected across said generator, said bridge being balanced by a tuned circuit, a track device adapted to render saidbridge unbalanced, an amplifier coupled to the Zero points of the balanced bridge, said amplifier being constructed and arranged to amplify the current flowing between the zero points of the bridge when the same is rendered unbalanced, and a relay associated with said amplifying means.

3. In arailwa signal device, the combination of a tram mechanism and a track mechanism,v the track mechanism being adapted to cooperate with said train mecha- D1Sm, Sa1d t1'a1I1 mechamsm COmPIISIDg an energized balanced bridge having in one arm thereof an oscillatory -circuit, said oscillatory circuit bein adapted to render the bridge unbalance in response, to the operation of the said track mechanism, and means coupled to the zero points of said bridge and adapted to actuate an indicating means when the bridge becomes unbalanced.

PAUL TA'rz, 

